Since portable work machines are carried by operators during work, the arms of the operator are strained. To reduce the strain, shoulder harnesses are used. Shoulder harnesses have a structure in which the upper body of an operator is surrounded by a harness network including at least a back member that is positioned on the back of the operator, and right and left shoulder belts that are connected to the back member.
FIG. 14 shows the outline of a shoulder harness disclosed in International Publication No. WO2008/076010 A1. A conventional first shoulder harness 1 shown in FIG. 14 includes an armpit belt 11 that is connected to a back member 2. A front end of the armpit belt 11 is joined with right and left shoulder belts SB on the front of an operator, to thereby constitute a harness network 4. A locking device 8, such as a hook, provided with a hip pad 5 is connected to the harness network 4. A work machine (not shown) is detachably attached to the locking device 8. To be more specific, a tunnel portion 5a is formed so as to extend laterally in an upper portion of the hip pad 5. One end of a single continuous suspension strap 6 that is inserted through the tunnel portion 5a is connected to the back member 2, and the other end thereof is connected to a chest plate of an operator. The hip pad 5 is also connected to the back member 2 by a suspension belt 7 as a second suspension member.
FIG. 15 shows the outline of a shoulder harness disclosed in U.S. Pat. No. 5,913,464. A harness network 13 of a conventional second shoulder harness 10 shown in FIG. 15 includes a first slant belt 11A that is connected to an upper end portion of the back member 2 and extends at a slant. The first slant belt 11A extends to the front of an operator at a slant downwardly along the left armpit of the operator from the upper end portion of the back member 2, and is joined with a waist belt 12. Therefore, the first slant belt 11A substantially constitutes an armpit belt. The waist belt 12 includes an extension portion 12a that is extended to the right side of an operator across the back member 2. A distal end of the extension portion 12a is connected to a second slant belt 11B that extends at a slant from the upper end portion of the back member 2. The locking device 8 provided with the hip pad 5 is connected to the harness network 13 via front and rear suspension belts 14 and 15. To be more specific, the front suspension belt 14 is connected to a joint portion between the first slant belt 11A and the waist belt 12, and the rear suspension belt 15 is connected to a joint portion between the extension portion 12a of the waist belt 12 and the shoulder belt SB.
FIG. 16 shows the outline of a shoulder harness disclosed in U.S. Pat. No. 6,247,624 B1 and International Publication No. WO2008/147256 A1. A conventional third shoulder harness 20 shown in FIG. 16 includes the armpit belt 11 and a waist belt 3 connected to the back member 2 to constitute a harness network 21. The locking device 8 provided with the hip pad 5 is connected to the harness network 21 via the front and rear suspension belts 14 and 15. To be more specific, the front suspension belt 14 is connected to the front end of the armpit belt 11, and the rear suspension belt 15 is connected to the back member 2. In FIG. 16, reference numeral 16 denotes a joint buckle that can be combined and separated. The joint buckle 16 is to be positioned on the chest of an operator.
FIG. 17 shows the outline of a shoulder harness disclosed in Japanese Patent Laid-Open No. 2005-143453. A conventional fourth shoulder harness 30 shown in FIG. 17 includes right and left armpit belts 31 and 32 connected to the back member 2 to constitute a harness network 33. The hip pad 5 including the locking device 8 is connected to the harness network 33 via the front and rear suspension belts 14 and 15. To be more specific, the front suspension belt 14 is connected to a front end of the left armpit belt 31, and the rear suspension belt 15 is connected to the back member 2.